A shooting at Pulse nightclub in Orlando, Fla., killed at least 49 and wounded 53, making it the deadliest shooting in U.S. history

Where It Happened

The shooting began around 2 a.m. Sunday at Pulse, a gay nightclub in downtown Orlando, Fla. Police shot and killed the suspected attacker, Omar S. Mateen, at about 5 a.m. after an hours-long standoff with police, Orlando Police Chief John Mina said. While the number of victims killed had previously been given as 50, Paul Wysopal of the Federal Bureau of Investigation clarified Monday morning that the total was 49.

The Shooter

Orlando Police Department/Reuters

Mateen, 29, of Port Saint Lucie, Fla., worked as a security guard, had a gun license and was a U.S. citizen. Mateen was born in the U.S. to parents from Afghanistan.

How the Tragedy Unfolded

Orlando Police officers direct family members away from a multiple shooting at a nightclub in Orlando, Fla., Sunday, June 12, 2016. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. PHOTO: Phelan M. Ebenhack/AP Photo

Around 2 a.m.The shooter opens fire outside Pulse nightclub, engages with an offduty uniformed police officer who was working for the nightclub when the shooting started, and then enters club. More officers arrive and exchange gunfire with the suspect, forcing him to stop shooting and retreat to one of the nightclub’s restrooms.

2:09 a.m.Pulse posts on its Facebook page:
"Everyone get out of pulse and keep running"

2:28 a.m.Shooter speaks with 911 dispatcher, pledges allegiance to Islamic State and prays in a foreign language.

After 2:30 a.m.Through messages with hostages, law enforcement officers learn that between five and eight hostages are being held by the shooter; another 15 to 20 people were hiding in another restroom.

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Police believe Mateen is holding several hostages in a restroom. Approximately 15 to 20 people were hiding in another restroom.

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Restrooms

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Police believe Mateen is holding several hostages in a restroom. Approximately 15 to 20 people were hiding in another restroom.

Bar

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Patio

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Restrooms

Entrance

Restrooms

Police believe Mateen is holding several hostages in a restroom. Approximately 15 to 20 people were hiding in another restroom.

Bar

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Stage

Patio

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Restrooms

Entrance

Restrooms

Police believe Mateen is holding several hostages in a restroom. Approximately 15 to 20 people were hiding in another restroom.

For about 90 minutes, police seek to find a peaceful end to the violence. Talks with crisis negotiators yield little from the gunman. Police are concerned about comments Mateen makes about having explosives, possibly a bomb vest.

Police believe another round of killing is imminent, based on messages from hostages inside the club. Authorities decide to storm the club to rescue as many people as possible.

Around 5 a.m.Police attempt to breach the back wall with an explosive device. But the breach only partially works, so police use an armored vehicle to ram the wall leading to the restroom adjacent to where Mateen is holed up.

SWAT team

sets up outside on the other side of the restroom wall.

Wall where police used an armored vehicle to create a hole

Entrance

SWAT team

sets up outside on the other side of the restroom wall.

Wall where police used an armored vehicle to create a hole

Entrance

SWAT team

sets up outside on the other side of the restroom wall.

Wall where police used an armored vehicle to create a hole

Entrance

Hostages are able to exit the building through the hole in the wall. At least 11 SWAT and other law-enforcement officials engage in the gunfight with Mateen.

Orlando Mayor Buddy Dyer said: "That’s when we took him down."

Investigators work at the scene of the shooting at Pulse nightclub in Orlando, Fla., on June 12, 2016.
PHOTO: Zachary Scheffer for The Wall Street Journal

Around 5:53 a.m.Orlando police announce over Twitter:
"Pulse Shooting: The shooter inside the club is dead."

After the shooter was killed, the police didn’t immediately enter the club because of concerns about possible explosive devices, Dyer said.

Diagram sources: Orlando Police Department; City of Orlando

The Deadliest Shooting in U.S. History

The number of fatalities surpassed the 32 victims from the Virginia Tech shooting in 2007, previously the largest number of people killed in an American mass shooting. Here are the deadliest mass shootings in U.S. history: